In state-space search, a state space is formally represented as a
tuple S: \langle S, A, \operatorname{Action}(s), \operatorname{Result}(s,a), \operatorname{Cost}(s,a) \rangle , in which: • S is the
set of all possible states; • A is the set of possible actions, not related to a particular state but regarding all the state space; • \operatorname{Action}(s) is the function that establishes which action is possible to perform in a certain state; • \operatorname{Result}(s,a) is the function that returns the state reached performing action a in state s; • \operatorname{Cost}(s,a) is the cost of performing an action a in state s. In many state spaces, a is a constant, but this is not always true. == Examples of state-space search algorithms==